The invention relates to a method for identification of manipulation to an arrangement comprising a sensor which emits pulses and a recording unit.
Particularly in the field of operating data recording for a commercial vehicle by means of a tachograph, it is essential to avoid manipulation on the basis of the original character of the recordings. In addition to the relevance of these recordings as evidence in legal disputes, the safety of the vehicle operation and labor-law aspects are also important here. With the new generation of digital tachographs in accordance with EU Order EU-VO 3821/85, these appliances are being developed against the requirement to reliably prevent manipulation of this new technology. One obvious method for deceitful manipulation of the recordings is the capability to modify, for example electromagnetically, the signal from a sensor which is generally fitted in the transmission area of the motor vehicle. For example, if the regularly pulsed signals from the sensor which are transmitted in real time could be delayed thus resulting in the recorded speed always being slower than the speed of travel.
One object of the invention is thus to make it harder to manipulate the transmission of a signal which is correlated with the distance traveled and/or with the speed from a sensor which emits pulses to a recording unit.